However, the party has denied this and leader Arlene Foster has criticised Mr Bell over his handling of the matter.

The DUP's Jeffrey Donaldson said Mr Bell had been suspended without prejudice.

"If you look at the DUP rules, Jonathan did not seek permission for the interview that he did," he said.

"He did not tell the party in advance what he was doing and that's not the way that most political parties operate."

Image caption
Arlene Foster said Mr Bell "took all the decisions" about the scheme during his time as minister

Mr Donaldson said Mrs Foster would not be "running away from her responsibilities".

"She's got nothing to hide, she's made absolutely clear she will make full disclosure of everything - all documents, papers, records of meetings," he said.

On Sunday afternoon, the DUP said it supported the need for an independent and speedy investigation and said the party had been working with officials to reach agreement on the details of such an inquiry.

The Assembly will debate a motion to exclude Mrs Foster as first minister on Monday.

According to Mr Bell, the advisers, who deny the allegations against them, secretly tried to "cleanse the record" of references to Mrs Foster.

Those alleged attempts to alter the papers were made "without my knowledge, without my consent", Mr Bell said, and were revealed to him by a senior civil servant at the department.

Sinn Féin's Conor Murphy has said the DUP needed to "do the right thing" over the issue.

"I don't believe that the DUP are immune from the anger that there is out there in the public," he said.

"This has placed a huge question mark over public confidence in the institutions and for that reason the DUP need to do the right thing - have their first minister step aside, agree to a full public independent inquiry and get to the core of these matters."

Meanwhile, Ulster Unionist leader Mike Nesbitt has said he has asked the Equality Commission to investigate Mrs Foster's "failure to act" after comments she made "revealing alleged knowledge of intimidation in the workplace".

"She clearly stated knowledge of alleged intimidation of female colleagues, yet with no apparent discharge of her duty of care to intervene," Mr Nesbitt said.

"If this isn't investigated, what motivation is there for others in positions of leadership to act to protect colleagues?"